Manufacture of a stable preparation from hydrogen peroxid and urea.



REINHOLD GR'U'TER AND HEINRICH POHL, OF OHABLOTTENBURG, GERMANY.

MANUFACTURE OF A STABLE PREPARATION FROM HYDROGEN PEROXID m UREA.

No Drawing.

To all whom it may concern: 7

Be it known that we, Rnmnono Gnii'rnu and HEINRICH Pour, residing atCharlottenburg, in the'Empire of Germany, have inv'ented certain new anduseful Improvements in the Manufacture of a Stable Preparation from Hdrogen Peroxid and Urea, of which the follbwing is a specification.

This invention relates to an improved process of producing stable doublecompounds of hydrogen peroxid and urea.

Tanatar (Uhemz'sches Centralblatt 1908 II, 583) has described theproduction of an less a addition product of the formula:

from urea and hydrogen peroxid by adding strong hydrogen and evaporatingthe mass in the water bath or in the exsiccator' over sulfuric acid. Theproduct which Tanatar obtained in this way is however, so unstable, asto be incapable of commercial introduction as a solid hydrogen peroxidpreparation, since this product which on formation contains 36 per cent.of

hydrogen peroxid, (as has been confirmed by experiments), is stated byTanatar to contain only 31.5 per cent. of H 0 after the lapse of 21 daysand only 15 per cent. after the lapse of 6 months.

We have now found thatthis product can be obtained in a more stable formwhen a small quantity of a substance of a .weakly acid nature is addedto the solution before We have found that the addition of very smallquantities of substances havin an acid reaction will reduce the liabilito the preparation to decomposition. Su stances which have not a stronglypronounced acidfor the purpose. are found to be character are most suitaStrongly acid substances vantageous. On the other hand quiteSpecification of Letters Patent.

Application filed September 12, 1911. Serial No. 848,895.

' added substance needs peroxid in encess to urea Th from that obtainPatented Oct. 8, 1912.

weakly acid substances, for instance uciu salts such as acid sodiumphosphate, sodium bitartate, boric acid and so forth, are found to actexcellently. The quantity of the only to be very small. A fraction ofone per cent. relatively to the quantity of urea will suflice.

We have further found that the double compound of urea and hydrogenperoxid can also be obtained in a more stable form by carrying out theproduction in a different way from that followed by Tanatar.

We have found that the double compound can be obtained from aqueoussolutions or from solutions in hydrogen peroxid, by crystallizationandseparation from the mother liquor.

e operation may advantageously consist in dissolving the urea in thewarm in strong hydrogen peroxid in excess, and crystallizing out bycooling. The double compound separates out in fine large crys tals ofabout one centimeter in length, very similar in outward appearance tothe urea crystals. It is found to contain 35.5-36 er cent. H O(theoretical proportions 36.1 1). The stronger the hydrogen. peroxidemployed the more closel does the oxy en content approximate to t etheoretical va ue.

The slight difference by which the preparation falls short of thetheoretical content of H 0 is probably due to some water taking part inthe crystallization. The preparation obtained by ciiystallization isdistinguished b this smal difference evaporation, which the theoreticalconlatter was obtained with tent of 36.17 per cent.

The stability of the glroduct obtained by crystallization can be rtherincreased by employing small additions of acidielding substances asbefore mentioned." T e crystals which separate out then contain tracesof the added substance. The mother liquor is then concentrated with theremainder of the added substance therein and likewise yields a stableproduct.

We claim The process herein described of producing 'a. stable doublecompound of hydrogen per- In testimony whereof we affix our signaoxidand urea, which comprises dissolving tures in presence of two witnesses.urea 'in hydrogen peroxid in excess and REINHOLD GRUTER. adding a smallquantity of a substance hav- HEINRICH POHL.

& ing an acid reaction and then crystallizing Witnesses: I

the double salt of urea and hydrogen per- PAULSGHULTZE, oxid from thesolution. I MAX MAETSCHKE.

